Connectors and socket housings are typically manufactured by injection molding precision grade polymers, such as ABS, LCP. For smaller volume applications the connectors and socket housings are often precision machined from a dielectric material. Metallic contacts are inserted into the socket housing and retained by some sort of mechanical interference or captured such that they do not fall out during use. In some cases, the contacts are inserted into the mold prior to injection such that the polymer material flows around portions of the contacts.
In both cases, the base material is typically loaded with glass fibers or particles to provide strength and mechanical or dimensional stability. In situations where thermal cycling is present during use or solder reflow attachment, the internal stress within the plastic/glass matrix can cause significant changes in dimension or flatness.
As interconnect products become more sophisticated, with higher pin counts, higher contact density, and higher signal and power integrity requirements, traditional methods of molding and machining are proving inadequate. High density connectors and sockets with fine pitches are very difficult to mold due to thin wall sections and fine features with large aspect ratios. It is also somewhat difficult to change from one configuration to another without producing a new mold. Machined housings are processed from raw stock, and are relatively expensive with long run times and limited capacity.